Electrically neutral organic liquid compositions



Nov. 13, 1951 Filed March e, 1947 G. E. F. BREWER 2,574,528 ELECTRICALLY NEUTRAL ORGANIC LIQUID COMPOSITIQNS vl?. SHEETS-SHEET l Nov. 13, 1951-. G. E. F. BREWER 2,574,528

ELECTRICALLY NEUTRAL ORGANIC LIQUID COMPOSITIONS Filed March e, 1947 2 SHEETS- SHEET 2 Waag IN VEN TOR.

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Patented Nov. 13, 1951 ELECTRICALLY NEUTRAL ORGANIC LIQUID COMPOSITIONS George E. F. Brewer, Detroit, Mich., assigner to Gage Products Company, Ferndale, Mich., a

corporation of Michigan Application March 6, 1947, Serial No. 732,804

5 Claims. l

The present invention relates to the control of the development of charges of static electricity as the result of agitation or movement of organic liquids relative to other substances.

It has long been known that electric charges are developed during the handling or use of certain organic liquids, and in many cases such charges are hazardous or objectionable. For example, they constitute a fire hazard in connection with the handling or use of inflammable hydrocarbon solvents, such as gasoline, dry

cleaning solvents and rubber solvents or plasticizers used in the milling of crude rubber. In the textile industry, they create an objectionable raising of the nap of certain fabrics.

A study of this phenomenon has established that when two bodies which are in contact with each other move relatively, an electric charge is developed. This results on relative movement of two solids, a solid and a fluid, or on relative movement between portions of a body of fluid. Then, when two electrodes are immersed in a body of liquid and moved relatively, and the electrodes are connected by an electric measuring circuit, a ilow of electricity through the circuit will be noted as long as the relative movement continues. In the case of organic liquids, which have a very high electrical resistance, very high potentials can build up, butfthe current flow may still be measured by a galvanometer and a sensitive amplifier. The magnitude of the current flow appears to follow the laws of fluid friction. Thus, within certain speed ranges, the

magnitude of the current flow is a lineal function of the square of the relative speeds for any given organic liquid and any given electrodes. The

current flow is extremely minute, if both elec-- trodes are relatively smooth metals, but is mutiplied many times if one of the electrodes is a porous material, such as wool, leather, cotton, silk or an acetate, and the other electrode is a metal. This explains the objectionable accumulations of electrical charges in dry cleaning operations.

In the past, it has been proposed that the difficulties encountered with frictionally produced charges in organic liquids be reduced by adding to the liquid a material, such as a soap, which will reduce its electrical resistance and, therefore, make possible a discharge of the frictional l electricity through the liquid, itself. By this means it has been possible to eiTect an appreciable reduction in resistance and, to some extent, to reduce the hazard of sparks. It is found, howi ever, that while such addition agents may reduce the resistance of a particular body of liquid to a substantial extent, no appreciable change in the current ow through the above described external measuring circuit occurs. Consequently, these addition agents do not remove the tendency of the system to generate frictional electricity, but act primarily to increase the rate of discharge of such electricity after it is generated. Thus, it is still possible for high potential differences to develop. This possibility of a high potential difference between the electrodes is vastly increased if the organic liquid between them is being violently agitated or is in the form of a spray, since in that case it does not form a continuous conductor. Such conditions are frequently encountered, for example in dry cleaning operations.

It has also been proposed that the static charges be dissipated or neutralized by the use of radioactive substances which emit positively charged rays that will neutralize any negative charge which may have been generated. So far as is known, no commercial use of this system has yet been made. In any event, it is relatively impractical because very powerful radiation would be required to pierce thick layers of material, thus endangering operators.

It is the general object of the present invention t0 provide a wide range of organic liquid mixtures suitable for use in many elds in which the property of generating frictional electric charges under the circumstances mentioned above may be controlled within relatively wide limits or may be entirely eliminated. As distinguished from the prior mixtures having a reduced electrical resistance, the mixtures of the present invention, although they may also have a reduced electrical resistance, are characterized by the fact that their capacity to generate a flow of electricity may be increased or entirely eliminated, as desired. In those cases in which the liquid mixtures have no capacity to generate an electrical charge (herein referred to as electrically-neutral mixtures), the reduced electrical resistance of the liquid is immaterial and it is unnecessary to provide means for discharging frictional electricity because none is generated.

In the drawings, the several views illustrate in graph form the capacity of a number of organic liquids and organic liquid mixtures to generate frictional electricity under similar conditions.

It has been found that each organic liquid will, under a given set of conditions, induce a current now differing from that of other organic liquids,

certain .liquids having a much greater power to generate a frictional electric charge than others. In accordance with the present invention, the power of any given organic liquid to generate an electric charge or create a flow of electricity under the conditions mentioned above may be either increased or :decreased by adding varying quantities oiv other organic liquids. In many cases, the frictional electricity generating power of the mixture passes through a maximum and minimum value on variations in the relative amounts of the organic liquids in the mixture.

While mixtures of all organic liquids which are mutually soluble evidence this lvariation in their power to generate frictional electricity, it

is the primary object of the present invention to provide solutions which are electrically-neutral, and it is found that, in general, such electricallyneutral solutions may be Vobtained by combinations of what are usually classified as nonpolar lorganic solvents, such Aas straight hydrocarbons `and halogenated -hydrocarbons'with volatile oxygen containing organic liquid compounds, which are Vusually classied Aas polar compounds, the

latter rgroup including alcohols, ethers, esters, ketones,.glycols, glycerols and other poly hydroxy alcohols. Since most'polar organic 'liquids have negligible current generating capacity, the invention ris primarily directed tothe problem of controlling that tendency in nonpolar organic liquids.

It is found `that ldissolving any polar organic compound of the type "mentioned in any nonpolar organic liquid, even in small amounts,

iradically aifects the power'of the nonpolar liquid to generate frictionalelectricity.Y In many cases, as gradually increasing amounts of `polar cornpounds are added to thenonpolar liquid, the capacity of the latter to generate frictional electricity is first rapidly increased and then drops 01T to zero or substantially zero at a concentration of the polar compound, which Vvaries with different nonpolar compounds but is in most cases approximately the same for a mixture of any givenpolar compound with all nonpolar organic liquids. In some cases, particularly when the polar compound is hexylene glycol, there is no linitial increase in the capacity t0 generate static electricity, all additions having the effect ,of reducing the generating capacity Yof the nonpolar organic liquid.

In any system comprising an organic electrode `and Aa metallic electrode, one of which is moved with respect to a common body of organic liquid, the capacity of the system to generate static electricity varies markedly with the character of the organic electrode. In general, the largest vcurrent values result when the organic electrode is wool cloth, while silk fabrics, chamois, rayon cloth, cotton cloth and mercerized acetate cloth generate progressively smaller current flows in the order in which they are enumerated.. However, when the capa-city to generate electricity vo1 a solution of a given nonpolar organic liquid Vwitha 'given polar compound is plotted against progressively increasing .amounts of the polar compound in the solution, the curves produced iby V'each of the above mentioned organic electrcdes xwi'll,` in most cases, reach their maximum and minimum at approximately the same percentages of polar compound in the solution. While the reason for different current readings for different organic electrodes is not known, rthere is reason to rbelieve that it is due more to .the-physical form than to the chemical compoktrcde materials.

sition of the organic electrode, the higher read ings being obtained with the materials which offer the greatest frictional `resistance to Y relative movement.

The properties `of nineteen representative ex-V amples of mixtures of polar and nonpolar organick withthe organic electrode material and immersedv .in the solvent; :The paddle was Velectrically insulated from the drive motor. The sole elecrical connection between the paddle andthe container q was through an external circuit containing an ex- .ceedingly sensitive amplifier and galvanometer. The electrical current Ithrough the external circuit was measured for the pure nonpolar liquid and forsolutionsorfthat liquid with progressively increasing quantities of a polar organic liquid.

The current values given on the following table are in terms of points on the galvanometer scale,

-but all of the vtests were run under identical conditions and, therefore, the values obtained on dif-V ferent tests may be compared to determined relative magnitudes, V.Each point Aon the galvanom- -eter scale is calculated to represent a current flow of 3 i11y11 amperes. Y

Incidentally, while all of the data Vgiven in the table were'obtained by testsin which the organic electrode was attached to the rotating paddle, other tests have established that substantially identical readings -are Aobtained when the organic 4electrode constitutes .the lining vof the .container and the paddle is the metal electrode.V

The first column on the `table lists the non# polar liquid in each of the mixtures The second column gives the current reading for the nonpolar liquid 'before any additions of polarV liquid were made.` The value'rgiven is that obtained when the -organic electrode was wool cloth, since that material rgave-the highest current readings of any of the yelectrode materials tested;

The third column lists the polar liquid which was addedin varying quantities to milliliters of the non-'polar liquid. Each of the solutions `was tested with a plurality of different organic elecent types of behavior were obtained with differ- In Vsome cases, initial additions of a polar'liquid increased the current readings to a maximum and further additions reduced the current readings to a minimum. Accordingly, in column 4 is listed the amount of polar liquid in milliliters'which was added to the 100 milliliters of nonpolar liquid to producethe maximumr current reading.

ferent organic electrode materials, a range of additive is given in column 4. Thus, for example,

in solutiont-S, in which the nonpolar liquid was f t naphtha and the Vpolar liquid was tertiary bu-V tanol, the addition of 16 millilitersV of tertiary butanol produced Amaximum current readings when the organic electrode was cotton or white acetate, an addition of approximately 25 to 30 milliliters of tertiary butanol produced the maximum current value for a chamois electrode, and an addition of 40 milliliters of tertiary butanol produced the maximum current for silk, Ve1` veteen, velvet and wool. Thus, in column 4, theVV It was found that two diier-A Y Since there were,U in some cases, variations in the maxima for difrange of additive for maximum current is given as from 16 to 40 for solution #8.

Column gives the value, in terms of galvanometer scale readings, of the maximum current cally-neutral so long as lt is approximately neu'- tral, and, accordingly, it is unnecessary to establish the solution ratio of absolute neutrality in all cases.

1 Remained neutral for larger additions up to 100 m1.

obtained by the additions listed in column 4 When 5 In order to set forth in greater detail the propthe organic electrode Was wool, this being the erties of certain of the solutions referred to in the highest reading in each case. In the case of above table, the actual curves showing the solution #18, two maxima, one positive and one amount of current generated with a Wool cloth negative, Vwere obtained. Consequently, in colelectrode for a number of solutions are shown in umns 4 and 5, figures for each of the maxima 10 the drawings in Figures l, 2 and 3. Thus, in Figare given. In addition, the amounts of ethyl ure 1 are shown the curves produced by additions ether are given in terms of percentage of the of normal butanol to three non-polar liquids, total solution by volume, rather than in millinamely carbon tetrachloride, naphtha and tolliters per 100 milliliters of the nonpolar comuene. The curves shown in Figure 1 are generpound. ally representative of the nature of the curves Column 6 gives the amount of polar liquid obtained with solutions of most polar and nonadded to produce a minimum current reading. polar organic liquids. Thus, it will be noted that This also is given as a range, partly because at in the case of carbon tetrachloride, the current exceedingly low current values it is diiicult to generating capacity of the pure nonpolar liquid determine the exact zero point and partly bewas 40 on the galvanometer scale but increased cause some slight divergence in the zero points to a maximum of almost 160 on the addition of of the curves was noted for different organic eleconly 10 milliliters of normal butanol. Further trode materials. In most cases, the minimum additions of normal butanol reduced the current current valuewas zero, as indicated by column generating capacity to only 6 unit at30 milli- 7, which lists the minimum current readings obliters of normal butanol and to zero at 50 millitained for al1 electrode materials tested. In some liters of normal butanol. A similar curve was obcases, no zero reading was obtained for some tained with naphtha except that the current genelectrode materials. For example, with solution erating capacity of the pure naphtha was ap- #6, carbon tetrachloride and tertiary butanol, the proximately 20 units, its maximum was 140, and curves for all organic electrode materials reached it reached a minimum of zero on the addition of a zero value at approximately 75 milliliters of approximately 38 milliliters of normal butanol. added tertiary butanol except for the curve for Toluene differed slightly in that it had a much wool, which reached a minimum at a scale readlower maximum, very little above the current ing of approximately 4 on the addition of 75 generating capacity of pure toluene. In the case milliliters of tertiary butanol. Accordingly, the of toluene, the current generating capacity was minimum current range for solution #6 is listed reduced to a very low value on the addition of in column 7 as from zero to 4. 25 milliliters of butanol and to zero on the addi- Amount of Amount of Current Polar Liq- Polar Liq- Minimum for 100% uid for Maximum nid for Current Nonponr Liquid, 100 miunirers bfi'gl rom Liquid Lggg (W221i Ngr'g (fgge (Wool (range for Electrode) (range for electrode Electrode) all electrode all electrode materials) materials) materials) Millilters Mzllliters 1 Carbon Tetrachlorlde (Fig. 1) 40 Normal Butanol 10 160 30 to 501 0 2 Toluene (Fig. 1). 60 ..do 0 60 20 to 501 0 s Naphthamig i) 20 1 13o roto 401 0 4 Benzeuel.. Oto 20 70 40 to 701 0 5 Naphth 1o 90 40 to 001 0 6 CarbonTetrachlorlde (Fig 20 300 70 to 80 0to4 7a Benzene 1g. 3) 0 to 10 90 70 to 100 0 to 4 8 Naphtha (Fig. 3) 16 to40 90 100 to 120 0to6 9 Mineralspiritsmigsy. 5 do 25 90 75to1o0 otoz 10 Mineral Spirits 5 Secondary Butanol..- 20 40 35 to 651 0 11 do n 5 Cyclohexanol 7.5 30 75 0 12 do 5 Hexanol 20 60 100 2 13. Mineral Spirits (Fig. 2) 5 Hexylene Glycol 0 5 20 to 251 0 14 Carbon Tetrachloride (F 40 do- 0 40 20 to 251 0 15 Tonen@ (Fig. 2) 00 o 60 2ot0251 o 16 Dlisobutylene 3 2 80 20 to 251 0 171 Carbon Tetrachloride 40 0 40 20 to 251 0 Positive, P o si- 181 do 40 Ethyl Ether (abso- 20 tive,40. 650, o

lute). Negative, Nega- 0 100%. tive, 90.

1 Negative dips for some electrode materials at lower concentrations than neutral. a Negative d ips for some electrode materials at higher concentrations than neutral.

It will be understood that the current values given in the above table are relative and are subject to the usual experi-mental errors unavoidable in measuring values of the magnitude here to utilize a solution which is absolutely electrition of 50 milliliters of butanol. The curves given in Figure l, since they are those obtained with the use of a Wool cloth electrode, are in general higher than those obtained With other organic electrode materials, but in general the maxima and minima of the curves occur at approximately the same additions of normal butanol.

In some cases, particularly When hexylene solvents, as indicated in vFigure 2.

milliliters.

4glycol is utilized as the polar liquid, strikingly different curves were obtained for most nonpolar As there shown, additions of hexylene glycol to carbon tetrachloride, toluene and mineral spirits produce Y,

no maxima, but in all-cases reduce the current generating capacity. This same characteristic was noted on additions of hexylene glycol to other nonpolar liquids, with the exception of diisobutylene, which, as indicated-on the above table,

produced a maximum current reading on the adthe currentgenerating capacity for all of the nonpolar liquids reaches zero on addition of the same amount of hexylene glycol, namely to 25 It was further noted that even with different organic electrode materials, the zero point was obtained at approximately the same addition of hexylene glycol. Moreover, in all cases on further additions of hexylene glycol', the

Vsolution remained neutral.

While in general all of the solutions tested produced curves conforming generally to the patterns appearing in Figures 1 and 2,somewhat more erratic curves were obtained with certain polar liquids, particularly tertiary butanol. Accordingly, the curves obtained by the additions of tertiary butanol to a number of nonpolar liquids are given in Figure 3. 'As there shown, the curve for carbon tetrachloride reached ,an exceedingly high maximum of 300 current-units on the addition of only 20 milliliters of tertiary butanol. This curve otherwise conforms to the general pattern of Figure l except that in no case didqthe curves reach the zero or neutral point when the wool cloth electrode was used. This latter characteristic was not noted for other electrode materials, all of which reached zero at approximately '75 milliliters of tertiary butanol and did not increase on further additions. The curves in Figure 3 for naphtha and mineral spirits are more or less conventional except that they reach their zero or minimum points at appreciably different additions of tertiary butanol. The curve for benzene is unique in that it has two maxima at additions of v10` and 30 milliliters of tertiary butanol, respectively. While the curves of Figure 3 are more erratic than those normally obtained, vit will be apparent that even in such cases it is possible to produce solutions which are neutral or substantially neutral with respect to their capacity to generate frictional electricity.

It will be apparent to those skilled in the art, from the diverse character of the numerous polar and nonpolar liquids listed in the above table, that comparable results may be obtained by a mixture of any polar organic liquid with any nonpolar organic liquid, so long as the two are mutually soluble. It will only Vbe necessary to determine by simple experiment the relative proportions of the two liquids required to produce the desired properties. Moreover, in cases where the selected polar and nonpolar liquids are not in themselves mutually soluble, either because of their inherent characteristics or because of the presence of some third material, they may be combined to produce the desired results by the use of a mutual solvent. For example, certain of the polar liquids listed in the above table are insoluble in the nonpolar liquidsif minute quantities of water are present. The presence of minute quantities of water is rendered likely; by

(see solution #13), separates completely in the presence of Aminute quantities of water. Itis v found, however, that additions ofv hexanol to-ithe,l solution maintain the two liquids in solution even though water is present. For this purpose, approximately one per cent hexanol is required for each one-tenth of one per cent of water present. Thus, a solution of milliliters of mineral spirits, 25 milliliters of hexylene'glycol, 13 milliliters Vof hexanol, and water not exceeding approximately 1.3 milliliters, produces a stable and electrically-neutral solution.

Other polar liquids, such as propylene glycol and glycerol, are similar to hexylene glycol in that they will not dissolve in certain of the nonpolar liquids, such as mineral spirits, in the presence of water, but may be so combined by additions of hexanol to produce a neutral solution. However, in the case of propylene glycol and glycerol, relatively large additions of hexanol are required to'produce the desired result, and this may be undesirable for some purposes. kther alcohols may be used as the mutual solvent, if desired, but the best results have been obtained with hexanol. .v L

Hexanol is itself a polar liquid capablek of Yproducing a neutral solution with aknonpolarrliquid, as indicated by solutiony#12 on the abovetable It is apparent, therefore, that in place of a single polar liquid, solutions of two or more polar liquids may be employed to neutralize nonpolar liquids in accordance with the principles outlined above.4 A Y Y i 'While in general itis not possible to vproduce entirely neutral solutions in the absence Yof a polar liquid, it has been found that combining two nonpolar Vorganic liquids in varying proportions materially affects theV current generating capacity of the solution and in some rare instances does produce a neutral solution. Thus, for example, solutions of benzene and carbon tetrachloride in almost all proportions have a` substantially constant current generating capacityV except that the current generating capacity is sharply decreased by from thirty to sixty per cent when the solution contains ap- L proximately sixty-iive per cent carbontetrac'hlo-- chloroform, alone, will generate a current of 9 unitsfor a woolelectrode Vbut may be rendered electrically neutral Vfor all electrode materials byY the addition of from 5 to 25 parts fofvhexylene glycol to 10 parts of chloroform under the cir,- cumstances described in connection with the above table. Y

In addition, in Figure 4 is illustrated'the effect on the frictional electricity generating capacity of variations in the Vproportions of solutions of chloroform and trichlorethylene.Y From -this -curve it will ber apparent tliat a very substantial increase in frictionalelectricity generating capacity is obtained at approximately seventy per cent trichlorethylene and thirty per cent chloroform. Another example of mixtures lof organic liquids which have `a striking Variation incur.- rent generating capacity is that comprising mixtures of benzeneand chloroform. While pure benzeneproduces a current generating capacity of approximately .50 'points on the -galvanometer scale under :the conditions described above and purev chloroform a current generating capacity of approximately 9 points on the galvanometer scale, a maximum of 200 points on the galvanometer scale is produced by a mixture containing seventy-five per cent benzene and twenty-five per cent chloroform.l

As a general-rule, the polar organic liquids have negligible current generating capacities in a pure state.V A striking exception has beennoted in the case ,of ethers. Thus, for example, under the conditions described above, pure ethyl ether produces a galvanometer reading of 90 points on the scale and isopropyl ether a reading of 40 points. Moreover, the polarity of the current generated in ethers is opposite to that generated in the nonpolar organic liquids referred to above. This explains the relatively high negative maximum reading obtained with pure ethyl ether, as noted on the above table in' connection with solution It has been found, further, that the relatively high negative current generating capacity of ethers may be neutralized completely by additions of other polar organic liquids in the same manner as the latter neutralize nonpolar organic liquids. Thus, three per cent ethyl alcohol or twenty per cent hexylene glycol will neutralize ethyl ether or isopropyl ether.

The advantage of increasing the frictional electricity generating power of an organic liquid has not hitherto been recognized, but there is evidence to support the conclusion that the tendency of such liquids to enter into chemical reactions is enhanced on an increase in their frictional electricity generating power.

While, as previously indicated, the electricallyneutral solutions of the present invention may be utilized to advantage in a wide variety of elds, it is believed that solutions of nonpolar dry cleaning solvents, such as carbon tetrachloride, trichlorethylene, naphtha or mineral spirits, with hexylene glycol of the formula are peculiarly useful for dry cleaning clothing, and particularly woolens. The practical'range for the proportions of such a solution is from approximately one and a half to three parts by volume of hexylene glycol to approximately six parts by volume of the nonpolar solvent. For this purpose, it is desirable that the solution also contain hexanol, in order to impart to the solution a tolerance to small quantities of water. From one-half to two parts by volume of hexanol in the above mentioned solution would ordinarily be suicient for this purpose, although greater quantities may be required if water in excess of one-fourth of one per cent is present. The complete solution is not only highly effective as a dry cleaning solvent, butl the mixture, because of its capacity to absorb water and dissolve water soluble materials, will obviate the necessity of using the customary dry cleaning soaps in most cases.

While other polar organic liquids may be substituted for hexylene glycol in dry cleaning solutions of the type mentioned, hexylene glycol or normal butanol are preferred because smaller quantities are required to produce an electricallyneutral solution.

The following table gives in parts by volume the range of quantities of different polar organic liquids required to produce substantially electrically-neutral solutions with ten parts by voll0 urne of any mutually soluble nonpolar organic liquid, and also the approximate quantity which appears to give the minimum frictional electricity generating capacity:

Range Hexylene glycol 11/2 to 10 21/2 Normal butanol 3 to 10 5 Iso-butanol 4 to l0 61/2 Tertiary butanol 7 to l6 15 Secondary butanol 5 to l0 61/2 Ethyl ether 10 to 20 15 Cyclohexanol 5v to 10 71/2 Hexanol 8 to12 l0 Methyl ethylketone 11/2 to 10 21/2 A range of proportions is given in part for the reason that commercial grades of the same compounds obtained from diiferent sources evidence appreciably different electrical generating capacity and in part for the reason that for many purposes it is unnecesary to obtain an absolutely neutral mixture in order to obtain the benets of the invention. Any solution coming within the ranges specified will have a current generating capacity materially less than that of the pure nonpolar liquid.

While numerous specific examples of organic liquid mixtures are specifically set forth herein, it will be apparent to those skilled inthe art that many other solutions of polar and nonpolar organic liquids are possible and that, by combining them in proper proportions, electrically-neutral solutions may be obtained within the spirit of the invention and the scope of the appended claims. While the examples given are all liquid solutions, it is believed obvious that the principles of the invention are applicable to solutions which are normally gaseous or solid. Thus, mixtures of polar and nonpolar gases which are electricallyneutral may be obtained. Likewise, organic solids, such as certain plastics and resins, may be made electrically-neutral by the addition of polar organic compounds which will remain in solid solution in the nal product.

What is claimed is:

1. An electrically-neutral liquid solution comprising approximately ten parts by volume of a nonpolar organic liquid which when substantially pure has the property of generating static electricity at an interface with a solid with which it is in mobile contact, and from one and one-half to ten parts by volume of hexylene glycol of the formula (CH3)z-COH'CH2CH(OH) -CII3.

2. An electrically-neutral liquid solution comprising approximately ten parts by volume of a nonpolar organic liquid which when substantially pure has the property of generating static electricity at an interface with a solid with which it is in mobile contact, from one and one-half to three parts by volume of hexylene glycol, and from onehalf to two parts by volume of hexanol.

3. An electrically-neutral liquid solution comprising approximately ten parts by volume of mineral spirits, from one and one-half to three parts by volume of hexylene glycol of the formula (CH3)2COH-CH2'CH OH)CH3, and from onehalf to two parts by volume of hexanol.

4. An electrically-neutral liquid solution comprising approximately ten parts by volume of mineral spirits and one and one-half to ten parts by Volume of hexylene glycol of the formula (CH3)2COHCH2CH(OH) -CH3.

5. In a system wherein a non-polar organic liquid selected from the class consisting of naptha, toluene, benzene, mineral spirits, and carbon Y einig-52e tetrachloride 'is in a container and is inrmobl vUNITEDSTATES-.PA'Ilill'-Sf i Contact With'a solid surface andwhere'inst'atic Number 'Name I A13m-el, Y electricity is produced by such contact when the 1,406,183 Y Ghegan Feb. 1.4. 1922 non-polar liquid is substantially pure, the im- 1775316 DOW 1 Sept''e; c1930,` provement in the system which comprises'V es- 5 1,551,361,713Y Le Comtek MS-7:3; 193% Y Sentially a hexylene glycol dissolvedin said non- 1911,289 Redd'sh Maygo; lga polar liquid in the proportion of one and one-half f v v Y to ten parts of said glycol to each ten parts of Y OTHER'REFERENCES A Said l10n-Dolar lqlld- Hackh--ChemicalDictionary '1944;pages` 1'1'4'9;

GEORGE E. F. BREWER;V m 409,@643, 66o. Y

` 1 Industrial and lEngineering Cheriiistry-'--Aal-V REFERENCES CITED lyticalEd., August 1947, 'pagsf8-600.``V 9 The following references are of record inthe Y Y le of this patent: 

1. AN ELECTRICALLY-NEUTRAL LIQUID SOLUTION COMPRISING APPROXIMATELY TEN PARTS BY VOLUME OF A NONPOLAR ORGANIC LIQUID WHICH WHEN SUBSTANTIALLY PURE HAS THE PROPERTY OF GENERATING STATIC ELECTRICITY AT AN INTERFACE WITH A SOLID WITH WHICH IT IS IN MOBILE CONTACT, AND FROM ONE AND ONE-HALF TO TEN PARTS BY VOLUME OF HEXYLENE GLYCOL OF THE FORMULA (CH3)2.COH.CH2.CH(OH).CH3.
 5. IN A SYSTEM WHEREIN A NON-POLAR ORGANIC LIQUID SELECTED FROM THE CLASS CONSISTING OF NAPHTHA, TOLUENE, BENZENE, MINERAL SPIRITS, AND CARBON TETRACHLORIDE IS IN A CONTAINER AND IS IN MOBILE CONTACT WITH A SOLID SURFACE AND WHEREIN STATIC ELECTRICITY IS PRODUCED BY SUCH CONTACT WHEN THE NON-POLAR LIQUID IS SUBSTANTIALLY PURE, THE IMPROVEMENT IN THE SYSTEM WHICH COMPRISES ESSENTIALLY A HEXYLENE GLYCOL DISSOLVED IN SAID NONPOLAR LIQUID IN THE PROPORTION OF ONE AND ONE-HALF TO TEN PARTS OF SAID GLYCOL TO EACH TEN PARTS OF SAID NON-POLAR LIQUID. 